1. Field
The described technology relates generally to a fuel injection apparatus and a fuel injection method and, more particularly, to an apparatus for injecting fuel into a cartridge for a fuel battery and a fuel injection method using the same.
2. Description of the Related Technology
A fuel cell is a device for electrochemically producing power by using fuel (hydrogen or reformed gas) and an oxidizing agent (oxygen or air). The fuel cell directly converts the fuel and the oxidizing agent into electrical energy through an electrochemical reaction. The fuel may be pure hydrogen or hydrocarbon-based fuel (such as LNG, LPG, or CH3OH). The oxidizing agent of the fuel cell may be oxygen or air containing a large amount of pure oxygen.
Different types of fuel cells include a polymer electrolyte membrane fuel cell (PEMFC), a direct oxidation fuel cell, and the like. A fuel cell using methanol as fuel, one of the direct oxidation fuel cells, is called a direct methanol fuel cell (DMFC). The direct oxidation fuel cell directly supplies fuel such as methanol, or the like, to a fuel cell stack to produce power according to a reaction between the fuel and an oxidizing agent. In the case of a small fuel cell, the DMFC supplies fuel to the fuel cell stack through a fuel cartridge. When the fuel stored in the fuel cartridge is used up, fuel is again injected to the fuel cartridge using a fuel injection device. Fuel injection devices measure the weight of the fuel cartridge, and thus, measure the amount of the fuel remaining in the fuel cartridge, and then replenish the fuel cartridge with fuel. With this method, however, the user must always measure both the weight of the empty cartridge and the remaining fuel amount, which is inconvenient to the user.
Also, when methanol stored in a container is exhausted, air is likely to be introduced. Because the weight of air is not measured, more fuel is “replenished” than is needed and the cartridge may be damaged through a continuous pumping operation. Further, when air is introduced into the interior of the fuel cartridge, there is no method for eliminating air, making it impossible to both accurately and completely fill the fuel cartridge with fuel. In addition, when air present in the interior of the fuel cartridge is supplied to the fuel cell stack, a phenomenon in which an anode is rapidly oxidized or density is not controlled occurs.